jeffstephens/retention-manager

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https://github.com/jeffstephens/retention-manager

Retention Manager

Automatically delete old images in a private Docker registry according to rules in simple YAML. Useful for keeping small Docker registries from consuming too much disk space. Use at your own risk and make sure you can recreate any mission-critical images!

Note: This doesn't actually free any disk space until you run Docker's garbage collection, which you should research and run separately. The main caveat is that if you run it while an image is being uploaded, it can corrupt the new image.

Configuration

You can define a rule for any number of repositories as follows:

yaml
registry: registry.example.com
policies:
  - repository: my-image
    maxTags: 5

The environmental variable CONFIG_PATH should point to this file on disk.

Example: Kubernetes CronJob

For a drop-in solution, check the helm/ directory!

A typical use case is a daily cron job. No additional Kubernetes permissions are required, but you do need to pass in your Docker registry credentials.

yaml
# create secret with credentials (don't forget to base64-encode)
apiVersion: v1
kind: Secret
metadata:
  name: secret-env
data:
  REGISTRY_PASSWORD: ...
  REGISTRY_USERNAME: ...
---
# create ConfigMap with config yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: retention-manager
data:
  config.yaml: |
    registry: registry.example.com
    policies:
      - repository: my-image
        maxTags: 5
---
# create CronJob referencing both of the following resources
apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: retention-manager
spec:
  # sometime overnight in California
  schedule: "11 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          volumes:
          - name: config
            configMap:
              name: retention-manager
              items:
                - key: config.yaml
                  path: config.yaml
          containers:
          - name: retention-manager
            image: jeffstephens/retention-manager:1.0.2
            imagePullPolicy: IfNotPresent
            env:
            - name: CONFIG_PATH
              value: /retention-manager/config.yaml
            - name: REGISTRY_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: secret-env
                  key: REGISTRY_PASSWORD
            - name: REGISTRY_USERNAME
              valueFrom:
                secretKeyRef:
                  name: secret-env
                  key: REGISTRY_USERNAME
            volumeMounts:
            - name: config
              mountPath: /retention-manager
              readOnly: true